Visible crew/equipment: In the episode where the doctor tries to save the woman who is drowning, when he enters the water for the second time just as he says "there's someone else out there", you can easily see the keel water of the boat or Jet Ski that is filming him.
Continuity mistake: When Charlie and Hurley are talking to Jack about the water, Jack then shouts something like, "I'm not making any decision," and in the background two people walk by - they move from right to left. After a cut to Charlie and Hurley when Hurley asks "Why?" it cuts back to Jack, and the same two people walk from right to left again.
Continuity mistake: When Sawyer asks of Boone, "So how does it feel?" Boone sits with his knees up and his arms crossed over his knees, but in Boone's close-up he sits normally with legs down, arms uncrossed. Then, as Sawyer walks away Boone sits just as in the first shot.
Continuity mistake: When Jack hangs off the cliff, he grips a vine covered in a multitude of leaves in the wideshots, but in the three tight close-ups his hand is dramatically shown slipping down a vine, without any leaves on or around it. He also remains at the same height position the entire time.
Continuity mistake: When Jack, Hurley and Charlie discuss water situation, the suitcase filled with water bottles repeatedly changes. One example: when Charlie carries the stuffed suitcase, then sets it down, it is open just a couple of inches, but when Jack walks away the suitcase is bursting with bottles, and is open at least 18-20 inches.
Continuity mistake: When Jack sees the casket, things lying on it change between shots. When he flips it open the ripped interior lining differs in the following shots, depending on camera angle. Then, as Jack destroys the coffin, the broken wood differs greatly between shots. Such as when the shot faces the coffin the entire top is destroyed, but when facing Jack the side frame remains intact.
Audio problem: While Claire is lying down, just after she says, "Our only hunter's gonna get eaten so he can get the pregnant girl some more water," we hear Charlie say, "I wouldn't worry about that," but his lips just begin to open mid-sentence, and he certainly doesn't say that.